title: Optically induced thermal gradients for protein characterization in nanolitre-scale samples in microfluidic devices.
abstract: Proteins are the most vital biological functional units in every living cell. Measurement of protein stability is central to understanding their structure, function and role in diseases. While proteins are also sought as therapeutic agents, they can cause diseases by misfolding and aggregation in vivo. Here we demonstrate a novel method to measure protein stability and denaturation kinetics, on unprecedented timescales, through optically-induced heating of nanolitre samples in microfluidic capillaries. We obtain protein denaturation kinetics as a function of temperature, and accurate thermodynamic stability data, from a snapshot experiment on a single sample. We also report the first experimental characterization of optical heating in controlled microcapillary flow, verified by computational fluid dynamics modelling. Our results demonstrate that we now have the engineering science in hand to design integrated all-optical microfluidic chips for a diverse range of applications including in-vitro DNA amplification, healthcare diagnostics, and flow chemistry.
authors.affiliation: Department of Biochemical Engineering, Torrington Place, University College London, London, WC1E 7JE, UK.
authors.forename: D M
authors.initials: DM
authors.lastname: Sagar
authors.forename: Samir
authors.initials: S
authors.lastname: Aoudjane
authors.forename: Matthieu
authors.initials: M
authors.lastname: Gaudet
authors.forename: Gabriel
authors.initials: G
authors.lastname: Aeppli
authors.forename: Paul A
authors.initials: PA
authors.lastname: Dalby
mesh_terms: D002138:Calibration; D044085:Microfluidics / Q000295:instrumentation*; D036103:Nanotechnology; D011506:Proteins / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D011506:Proteins